回复：这解有点杀鸭用牛刀的味道。
duck_donald
2010-04-22 09:20:42
( reads)
A: the area is defined by x=0, y=0, x=60, y=60, y=x-20 and y=x+20.
B: the area is defined by x=0, y=0, x=60, y=60.
The probability = A/B = 5/9.
jinjing
2010-04-23 17:51:46回复：回复：这解有点杀鸭用牛刀的味道。